The present invention generally relates to an automotive fuel pump for use with an automobile engine.
The regenerative fuel pump with a ring impeller is well known in the industry especially for lower voltage, high pressure applications. However, this type of fuel pump has disadvantages when used in higher flow, hot fuel applications. For proper performance, it is desirable that the pump supply only liquid fuel to the fuel injectors of the automobile. Ring impeller pumps when used in high flow, hot fuel applications tend to generate fuel vapors due to the high turbulence of the high pressure flow. When the fuel is hot, the fuel will more easily transform into vapor, thereby compounding the vapor problem.
Traditional pumps, such as those described in U.S. Pat. Nos. 5,024,578 and 5,336,045 have attempted to resolve this problem by increasing the width of the flow channel within the fuel pump, expanding the flow channel outward radially. This does not solve all the concerns however, because the flow channel cannot extend outward beyond the radius of the ring impeller. Additionally, the ""045 patent and the ""578 patent also describe a flow channel with increased depth. This flow channel profile is only useful for relatively lower flow rates of about 100 liters per hour. The wider and deeper flow channel concepts do not solve the vapor concerns in a high flow ring impeller application. Therefore, there is a need for an improved ring impeller fuel pump suitable for high flow and hot fuel handling situations.